The present invention relates to a new antimony compound, more particularly to an organoantimony compound and its use in chemical vapor deposition processes to produce antimony-containing semiconductor materials.
A variety of semiconductor systems containing antimony have been investigated for applications in infrared detectors, high speed devices, optoelectric devices, and magnetic position sensors.
Antimony-containing binary materials, e.g. InSb and GaSb, as well as ternary and quaternary materials, e.g. InAs.sub.1-x Sb.sub.x and InAs.sub.1-x-y Sb.sub.y Bi.sub.x, have been grown heteroepitaxially by organometallic vapor phase epitaxy (OMVPE), a high throughput technique for the production of high quality semiconductor materials from organometallic precursors such as organoantimony compounds.
Certain semiconductor materials have been grown by OMVPE using trimethylantimony or triethylantimony as the organoantimony source compound. Attempts at low growth temperatures resulted in significant problems due to the incomplete pyrolysis of these organoantimony compounds.
An alternative organoantimony precursor for OMVPE is needed which has a lower pyrolysis temperature than the above trimethyl and triethyl antimony compounds. It is also important that such alternative organoantimony precursor pyrolyze with minimal unintentional impurity incorporation. Recently, triisopropylantimony, ((CH.sub.3).sub.2 CH).sub.3 Sb, was used to grow epitaxial InSb films at temperatures as low as 300.degree. C. However, triisopropylantimony has a low vapor pressure in comparison to trimethylantimony and very low film growth rates resulted. An organoantimony precursor with a higher vapor pressure and a low decomposition temperature is still needed.
It has been demonstrated that the presence of one or more hydrogens bonded to the Group V precursor helps minimize unintentional carbon incorporation into the semiconductor film. However while Group V hydrides such as AsH.sub.3 and PH.sub.3 are commonly used with Group III trialkyls (R.sub.3 M: M.dbd.AI, Ga, In; R.dbd.Me and Et) in the growth of III/V semiconductors, SbH.sub.3 is unstable at room temperature and is inconvenient to use since it is not commercially available and must be generated at the place of use. A few primary (RSbH.sub.2) and secondary stibines (R.sub.2 SbH) have been reported, they are unstable and not commercially available. This contrasts with the primary and secondary phosphines and arsines which are stable and commercially available. Furthermore, problems associated with toxicity, high pressure gas storage hazards, transportation restrictions, and high temperatures required for the pyrolysis of these Group V hydrides have resulted in the development of alternates non-hydride Group V source compounds for OMVPE. Since SbH.sub.3 is unstable and inconvenient to use, trimethylantimony and triethylantimony are the conventional Sb source compounds used in OMVPE.
The use of Bi in IR detectors has shown to be useful in reducing the band gap of such detectors; however, higher growth temperatures (400.degree. C. and above) results in poor Bi-containing-film morphology. In order to minimize the tendency of the Bi to phase separate and to limit the diffusion in these alloys by lowering the film growth temperature, an alternative organoantimony precursor for OMVPE is needed which has a lower pyrolysis temperature than trimethylantimony.
The availability of alternative Sb source compounds for OMVPE could greatly enhance the development of antimony-containing semiconductor materials. Development of new Sb source compounds for chemical vapor deposition processes is of interest for lowering the film-growth temperature of Sb-containing semiconductor materials and altering the chemistry to minimize unintentional impurities.
One object of the invention is the provision of an improved organoantimony source compound for antimony-containing semiconductor materials.
Another object is to provide an organoantimony precursor for OMVPE for the production of antimony-containing semiconductor materials having a higher vapor pressure and a lower decomposition temperature than organoantimony precursors heretofore used.
Still another object is the provision of a novel organoantimony precursor which pyrolyses with minimal unintentional impurity incorporation into the antimony-containing semiconductor material.
A still further object is to provide a process for preparing such antimony source compound or precursor for production of antimony-containing semiconductor materials.
Yet another object is the provision of a process of forming an antimony-containing semiconductor material by chemical vapor deposition, using an improved organoantimony source compound.